Reference is made to commonly assigned, U.S. patent application Ser. No. 09/464,555, now U.S. Pat. No. 6,354,431, entitled: DARK BOX-TRANSFER APPARATUS AND MANUFACTURING SYSTEM, filed in the names of Michael DeCecca, Joseph A. Watkins, and Duane B. Kirk each of which is assigned to the assignee of this application.
The invention relates to positioning equipment and methods for manufacturing and more particularly relates to a registration mechanism and method.
A variety of procedures are known in which one-time use cameras are loaded with film, and the film is prewound in the dark. An example of this kind of procedure is disclosed in U.S. Pat. No. 5,689,876. During film loading, a onetime use camera frame assembly, that is, a camera or incomplete camera subunit, is moved through a series of workstations by a rotary turntable or a conveyor. A dark box encloses the film loading workstations. Camera frame assemblies enter and leave the dark box through light-lock doors. Dark conditions are maintained during film loading steps until the camera frame assemblies are light-tightly closed by installation of camera backs.
For film loading, accurate positioning of the camera frame assemblies in the workstations is critical. Rapid movement from station to station is highly desirable. Accurate positioning of the camera frame assemblies during transit between workstations is not important. U.S. Pat. No. 4,331,229 discloses a manufacturing machine in which pallets are moved from the station to station on a conveyor belt. At each station, the pallet is lifted from the belt and accurately positioned for access by the tooling of that workstation. The manufacturing machine of this patent provides accurate positioning at the workstations and can provide rapid movement from station the station. The manufacturing machine has the shortcoming; however, that exacting measures must be taken independently, at each station, to insurer accurate positioning. This may also be a strength, in general use under lighted conditions, since it would appear that a workstation could be serviced without necessarily disaccommodating the remainder of the manufacturing machine. Dark conditions would make this impractical, since use of light during servicing would avert usage of all the workstations.
A variety of different apparatus and methods are known for transporting and registering pallets and workpieces, such as U.S. Pat. Nos. 3,888,341; 4,148,400; 4,201,284; 4,394,897; 4,850,102; 4,854,532; 5,058,251; 5,062,188; 5,167,589; 5,197,172; 5,226,211; and 5,242,043. Features disclosed in one or more of these patents include use of a transfer bar, pallet clamping, and pallet locating using multiple, orthogonally arranged support points. Various of the disclosed devices have a number of shortcomings, such as: complexity; excess moving mass that is necessary for a high weight carrying capacity, but is excessive for light, rapid manufacturing; overconstrained registration mechanisms requiring more than a minimum of precision parts, and pallet movement systems that require precision parts that are subject to high rates of wear during use.
It would thus be desirable to provide an improved registration mechanism and method which is simple, not overconstrained and requires a relatively low number of precision parts.
The invention is defined by the claims. The invention, in some of its broader aspects, provides a registration mechanism that has a datum unit and a bolster movable toward and away from the datum unit. First, second, and third pins are mounted to the bolster. At least one spring resiliently biases the pins outward from the bolster. A pallet is supported by the pins between the bolster and datum unit. The pallet has first, second, and third sockets aligned with respective pins. The pallet has a registering face facing the datum unit. The registering face is disposed opposite the sockets. The pallet is movable by the bolster toward the datum unit from a lowered position. In the lowered position, the registering face is spaced from the datum unit and respective pins and sockets are spaced apart. In a first intermediate position, the registering face is spaced from the datum unit, and the sockets rest freely on respective pins. In a second intermediate position, respective sockets and pins are pressed together in partial counteraction of the resilient biasing. In a raised position, the registering face and datum unit are clamped together and the sockets are immobilized relative to the pins.
It is an advantageous effect of at least some of the embodiments of the invention that an improved film loading apparatus is provided which is relatively quick and easy to set up and in which camera frame assemblies can be rapidly moved between workstations and accurately positioned in workstations.